Abstract: A radio-frequency quadrupole ion guide having a symmetrical magnetic field disposed along an axis of the ion guide, wherein the system provides prolonged interaction between electrons and uncharged compounds within an ionization volume of the ion guide, resulting in enhanced ion creation.

Abstract: A method and apparatus for focusing ions for delivery to an ion detection device using an aerodynamic ion focusing system that uses a high-velocity converging gas flow at an entrance aperture to focus an ion plume by reducing spreading and increasing desolvation of ions, and wherein a voltage is applied to at least a portion of the aerodynamic ion focusing system to assist in the focusing and delivery of ions to the ion detection device.

Abstract: The present invention is embodied in a method and apparatus for utilizing inherently insulative material, such as the glass and epoxy resins used in construction of printed circuit boards, for construction of components in a time of flight mass spectrometer. By using printed circuit board materials, the present invention can take advantage of fabrication techniques for providing circuit traces on surfaces, from one side to another as a via, or embedded within the printed circuit material so as to be covered except where necessary to be exposed to make contact with other electrical devices. Embedded circuit traces also enable capacitive coupling to AC energy while maintaining electrical and physical isolation. Consequently, the present invention enables both invasive and non-invasive access to pressure and vacuum chambers.

Abstract: The present invention is embodied in a method and apparatus for transporting ions via a path generated by RF electrodes having a controllable DC field gradient generated thereon which does not suffer from mass discrimination. In a preferred embodiment, the number of electrodes are doubled to thereby use symmetry to cancel an undesirable DC quadrapole field. By eliminating the DC quadrapole field, the passband of the DC field gradient is increased, allowing for ions of higher mass to be transported. The electrodes are either tilted or tapered to thereby generate the desirable DC field gradient. Tilting and/or tapering the electrodes advantageously modifies the DC field gradient to increase the high ion mass cut-off.

Abstract: A method and apparatus for collimating ions being emitted from a supersonic expansion nozzle for injection into a time of flight mass spectrometer. Radio frequency fields are used to focus ions toward a desired path, while energy is dissipated from the ions by using a background gas which is advantageously part of a supersonic expansion, giving the background gas a highly organized velocity profile. The background gas absorbs energy when the ions collide with the background gas molecules. By causing the collisional cooling between the ions and the background gas molecules to occur within the supersonic expansion, the ions do not receive velocity distributions determined by ambient thermal energies, but instead enables generation of a highly collimated and high intensity ion beam directed toward the time of flight mass spectrometer.

Abstract: Dissociations of multiple-charged ions are detected and analyzed by charge-separation tandem mass spectrometry. Analyte molecules are ionized to form multiple-charged parent ions. A particular charge parent ion state is selected in a first-stage mass spectrometer and its mass-to-charge ratio (M/Z) is detected to determine its mass and charge. The selected parent ions are then dissociated, each into a plurality of fragments including a set of daughter ions each having a mass of at least one molecular weight and a charge of at least one. Sets of daughter ions resulting from the dissociation of one parent ion (sibling ions) vary in number but typically include two to four ions, one or more multiply-charged. A second stage mass spectrometer detects mass-to-charge ratio (m/z) of the daughter ions and a temporal or temporo-spatial relationship among them. This relationship is used to correlate the daughter ions to determine which (m/z) ratios belong to a set of sibling ions.

Abstract: In an ion cyclotron resonance mass spectrometer, ion cyclotron resonance signals at higher harmonics of cyclotron frequency are employed to increase the resolution of ICR mass spectrometer without increasing the magnetic field. The detection electrodes consist of M (where M is an integer) identical electrodes arranged in M-fold symmetry about the axis of the coherent cyclotron motion of the observed ions. In an ion cyclotron having four points of voltage in space, the cyclotron electrodes are set up in clockwise symmetric fashion. To increase the resolution in signal detection resulting from the potential induced by ions moving in orbits in the specrometer, the first and third voltages are added and the second and fourth voltages are subtracted from the sum of the first and third voltages.